Brown plans to pursue a massive project to move water from the Sacramento area into the Central Valley and Southland and help restore the ravaged delta habitat.

More than 100 people demonstrated at the California Capitol against Gov.… (Rich Pedroncelli, Associated…)

Gov. Jerry Brown's administration said Wednesday that it is pushing ahead with a $23-billion proposal intended to improve water deliveries to the San Joaquin Valley and Southern California and stop the ecological free fall of the Sacramento-San Joaquin Delta.

The plans, which would involve construction of the most ambitious water supply project in California in decades, call for the building of two massive tunnels beneath the delta to transport water south, and the restoration of tens of thousands of acres of delta habitat.

Invoking California's "pioneer spirit," Brown said the project was "profoundly important to California's future" and called it "a big idea for a big state."

"I look at this as another test of whether we can govern ourselves," he said at a Sacramento news conference, at which he was joined by U.S. Interior Secretary Ken Salazar. "Analysis paralysis is not why I came back. I want to get [stuff] done," he said, using an expletive to emphasize his resolve.

Under the proposal, which is a scaled-down version of an earlier design released during Gov. Arnold Schwarzenegger's administration, three large intake facilities would be built on the Sacramento River near Hood. They would be capable of diverting 9,000 cubic feet of water a second into two side-by-side underground tunnels that would carry supplies 35 miles to the huge government pumps in the south delta that send water to Central Valley farms and Southland cities. Currently, supplies are drawn through the delta to the pumps, a system that has profoundly altered the delta ecology.

Water users — ultimately farmers and residential customers — would foot the $14-billion construction bill and roughly $5 billion in operating costs. State taxpayers would cover most of the $3-billion to $4-billion expense for habitat restoration.

Though Brown's announcement signaled momentum after years of planning, the proposal remains far from a sure thing. Key issues remain unsettled — most important, the volume of water that would be exported from the delta system.

If the water agencies paying for the new conveyance facilities can't be assured of the deliveries they want, they could pull out. The project must also win permits from the state and federal agencies responsible for enforcing endangered species protections.

Officials said alternatives, including building larger or smaller facilities, will remain under consideration while they try to nail down details of their preferred proposal in coming months. They are hoping to release draft environmental documents this fall and issue a final decision next year. Under the most optimistic time frame, construction could begin in two to three years, and the project would be up and running in 2026.

The tunnel proposal echoes the peripheral canal project that Brown, in an earlier term as governor, pushed through the Legislature, only to see it killed by voters in 1982. Brown said the new project is based on a much better understanding of the delta ecosystem and the effects of delta pumping. "Here we are 30 years later with a lot more knowledge, a lot more science and better technology," he said.

The plan for a new system to ship Northern California water supplies south is the latest in 20 years of efforts to resolve the conflict between the state's thirst and the environment of the West Coast's largest estuary.

As water exports rose in recent decades, the health of the delta has deteriorated sharply. Its native fish are imperiled, its waters infested with invasive species. The delta's basic hydrology has been thrown out of whack by the enormous south delta pumps that are so powerful they reverse the flow of delta waterways.

With environmental decline have come tighter export restrictions that cut water deliveries to the Southland and San Joaquin Valley agribusiness. The premise of the new proposal is that by combining new conveyance facilities with extensive habitat restoration, the delta environment will improve, fish species will rebound and water deliveries will stabilize or grow.

But environmentalists and delta advocates argue that the only way to save the delta is to take less water from it. "They can't prove [the project] will work for the environment," said Jonas Minton, a former state water official who is now water policy advisor for the Planning and Conservation League. The estuary "needs more fresh water to sustain it, and they continue to deny that," he added.

The proposal to build a peripheral canal around the delta to carry supplies to the pumps sparked a nasty north-south battle 30 years ago.

But political opposition to the tunnel proposal has so far been centered in the delta, which has limited political clout and has aimed its guns at corporate agriculture rather than Southern California — recognition that most of the water diverted from the delta goes to irrigation ditches, not urban faucets.